HIV transmission networks mapped to reduce infection rate

Researchers at the University of California, San Diego School of Medicine have mapped the transmission network of human immunodeficiency virus (HIV) in San Diego. The mapping of HIV infections, which used genetic sequencing, allowed researchers to predictively model the likelihood of new HIV transmissions and identify persons at greatest risk for transmitting the virus.

The findings are published online in the June 5 issue of the journal PLOS ONE.

"The more we understand the structure and dynamics of an HIV , the better we can identify 'hot spots' of transmission," said Susan Little, MD, professor of medicine at the UC San Diego AntiViral Research Center and lead author of the study.

"Not everyone who is HIV-infected is equally likely to transmit the infection to others. There are clusters of more active disease transmission. We can use this information to target treatment interventions to those most likely to transmit the virus to others and markedly reduce the number of new infections."

The researchers analyzed the HIV-1 sequence data from recently HIV-1 infected persons and their sexual and social contacts in San Diego, between 1996 and 2011. Sequence data were collected as part of routine HIV genetic testing used to determine if a virus is resistant to certain classes of HIV medications. Genetic similarities between viral sequences infecting different people were compared. Viruses from two people with a high degree of genetic similarity were suggestive of a transmission link. The scientists noted that viral similarity does not independently prove that a transmission occurred, only that the individuals are part of a closely connected transmission network.

Within the observed HIV transmission network, researchers calculated a transmission network score (TNS) to estimate the risk of HIV transmission from a newly diagnosed individual to a new partner. Participants with a high TNS were significantly more likely than those with low TNS to develop a close linkage to another person within their first year of HIV infection, suggestive of onward transmission.

Through network modeling, investigators showed that using this information to deploy antiretroviral therapy (ART) to individuals with the highest TNS resulted in a significantly greater likelihood of reduced new HIV-1 transmissions than providing ART to the same number of randomly selected individuals.

"Focusing our prevention and treatment resources to the populations at greatest risk of transmission could dramatically reduce the number of new infections associated with these populations," said Little. "Used in conjunction with traditional partner services, TNS-guided treatment and prevention interventions could markedly lower rates of new HIV infection in our community."

add to favorites email to friend print save as pdf

Related Stories

In Africa, STI testing could boost HIV prevention

May 28, 2014

To maximize HIV prevention efforts in South Africa and perhaps the broader region, public health officials should consider testing for other sexually transmitted infections when they test for HIV, according to a new paper ...

Good news for HIV treatment as prevention

Mar 07, 2014

The Kirby Institute at UNSW Australia welcomes early results from the PARTNER study, which has found that HIV positive gay men who are on treatment and have undetectable viral load are not transmitting HIV ...

Recommended for you

South Africa's life expectancy jumps to 61.2 years

19 hours ago

Life expectancy in AIDS-hit South Africa has shot up sharply over the past decade, thanks to life prolonging anti-retroviral (ARVs) treatment, latest estimates from the country's statistics agency showed Thursday.

User comments